The present invention relates to a resin-packaged semiconductor device surface-mountable onto an object surface such as a circuit substrate, and more specifically, to a semiconductor device suitably used as a light emitter or a light receiver of an optical sensor.
Referring to the attached drawings, FIG. 29 and FIG. 30 show a typical conventional resin-packaged semiconductor device. This semiconductor device Y is a light emitting diode (LED) of a so-called frame type, made from a lead frame obtained by punching a metal plate for example.
Specifically, the light emitting diode Y comprises a pair of leads 1, 2 respectively including inner terminals 10, 20 and outer terminals 11, 21, a semiconductor chip (light emitting element) 3 mounted to the inner terminal 10 of the lead 1, a wire W for connecting an upper surface 30 of the light emitting element 3 to the inner terminal 20 of the other lead 20, and a resin package 4 for sealing the inner terminals 10, 20 of the leads 1, 2, the light emitting element 3 and the wire W. The resin package 4 is formed to have a convex lens 46 right above the light emitting element 3. Each of the outer terminals 11, 21 is bent like a crank so that the tip portion 11a, 21b is flush with a bottom surface 45 of the resin package 4.
With the above arrangement, the light emitting diode Y is surface-mounted on an object surface 5 such as a circuit substrate, and used as a light source for various purposes such as a light source of an optical sensor. When the light emitting diode Y is surface-mounted to the object surface 5, so called solder re-flow method is generally used. When the light emitting diode Y is mounted by means of the solder re-flow method, first, cream solder is applied to the tip portions 11a, 21a of the outer terminals 11, 21 for example. Then, the light emitting diode Y is lowered, with its tip portions 11a, 21a being aligned with their corresponding terminal pads 50 on the object surface 5, and then is placed in a re-flow furnace. In the re-flow furnace, the solder paste is re-melted under a temperature of about 200xc2x0 C. When the melted solder sets again, the light emitting diode Y is fixed on the object surface 5, completing the mounting process.
However, according to the light emitting diode Y, only the tip portions 11a, 21a of the outer terminals 11, 21 serve as the mounting portions to be fixed onto the object surface 5. This unitary determines the direction in which the light emitting diode Y can be faced. Specifically, if the upper surface 30 of the light emitting element 3 serves as the light emitting surface, the light emitting diode Y can only be mounted so as to emit light upward with respect to the object surface 5, or in other words, the light emitting diode Y cannot be mounted for emitting in parallel to the object surface 5. Therefore, in order to emit in parallel to the object surface 5, another light emitting diode must be prepared in which the emitting surface is vertical with respect to the bottom surface 45 (mounting surface) of the resin package 4. As exemplified as above, according to the conventional light emitting diode, there is an inconvenience in that different kinds of the light emitting diode must be prepared depending on the direction in which the light is to be emitted. The same inconvenience can also pose a problem in such semiconductor devices as a photodiode and a phototransistor in which a light receiving element is used as the semiconductor device chip 3.
It is therefore an object of the present invention to provide a semiconductor device capable of solving the above described problem.
According to a first aspect of the present invention, there is provided a semiconductor device comprising a semiconductor chip, a first lead connected to an electrode of the semiconductor chip, a second lead connected to another electrode of the semiconductor chip, and a resin package sealing the semiconductor chip, an inner terminal of the first lead, and an inner terminal of the second lead, wherein the resin package includes a first to a fourth side surfaces, an upper surface and a bottom surface, and each of the first and the second leads includes at least one outer terminal located near a corner portion of the resin package and extending along a same side surface of the first to the fourth side surfaces and the bottom surface of the resin package.
According to the above arrangement, an anode/cathode pair is formed at least in one of the side surfaces and in the bottom surface of the resin package. Therefore, when mounting the semiconductor device onto an object surface such as a circuit substrate, either of said one side surface and the bottom surface can be selected as a mounting surface.
According to an embodiment of the present invention, the outer terminal of the first lead includes a drop portion extending from the corresponding inner terminal along the first side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the third side surface of the resin package. The outer terminal of the second lead includes a drop portion extending from the corresponding inner terminal along the first side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the fourth side surface opposite to the third side surface of the resin package.
According to another embodiment of the present invention, the outer terminal of the first lead includes a drop portion extending from the corresponding inner terminal along the first side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the third side surface of the resin package, wherein the outer terminal of the second lead includes, a drop portion extending from the corresponding inner terminal along the second side surface opposite to the first side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the third side surface of the resin package.
According to still another embodiment of the resent invention, the outer terminal of the first lead includes a drop portion extending from the corresponding inner terminal along the third side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the third side surface of the resin package, wherein the outer terminal of the second lead includes a drop portion extending from the corresponding inner terminal along the third side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the second side surface opposite to the first side surface of the resin package.
According to still another embodiment of the present invention, the outer terminal of the first lead includes two branch portions, and one of the branch portions is bent to extend along the first side surface and the bottom surface of the resin package, whereas the outer terminal of the second lead includes two branch portions, and one of the branch portions is bent to extend along the first side surface and the bottom surface of the resin package. In this case, the other branch portion of the outer terminal of the first lead extends along the first side surface beyond the third side surface of the resin package whereas the other branch portion of the outer terminal of the second lead extends along the first side surface beyond the fourth side surface opposite to the third side surface of the resin package. Alternatively, the other branch portion of the outer terminal of the first lead is bent to extend along the first side surface and the third side surface of the resin package whereas the other branch portion of the outer terminal of the second lead is bent to extend along the first side surface and the fourth side surface opposite to the third side surface of the resin package.
According to still another embodiment of the present invention, the outer terminal of the first lead includes two branch portions, one of the branch portions is bent to extend along the first side surface and the bottom surface of the resin package, and the other branch portion is bent to extend along the first side surface and the third side surface of the resin package, whereas the outer terminal of the second lead includes two branch portions, one of the branch portions is bent to extend along the second side surface opposite to the first side surface and the bottom surface of the resin package, and the other branch portion is bent to extend along the second side surface and the third side surface of the resin package.
According to still another embodiment of the present invention, the outer terminal of the first lead includes two branch portions, one of the branch portions is bent to extend along the third side surface and the bottom surface of the resin package, whereas the outer terminal of the second lead includes two branch portions, and one of the branch portions is bent to extend along the third side surface and the bottom surface of the resin package. In this case, the other branch portion of the outer terminal of the first lead extends along the third side surface beyond the first side surface of the resin package, and the other branch portion of the outer terminal of the second lead extends along the third side surface beyond the second side surface opposite to the first side surface of the resin package. Alternatively, the other branch portion of the outer terminal of the first lead is bent to extend along the third side surface and the first side surface of the resin package, whereas the other branch portion of the outer terminal of the second lead is bent to extend along the third side surface and the second side surface opposite to the first side surface of the resin package.
Preferably, the semiconductor chip is mounted on the inner terminal of the first lead, and the inner terminal of the second lead is connected to the semiconductor chip via a wire. Further, it is especially advantageous if the connection between the inner terminal of the second lead and the wire is made generally at a longitudinal center of the resin package. Further, if the semiconductor chip is a light emitting element or a light receiving element, the upper surface of the resin package may be provided with a convex lens portion at a location corresponding to the semiconductor chip.
According to a second aspect of the present invention, there is provided a semiconductor device comprising a semiconductor chip a resin package sealing the semiconductor chip, four outer terminals outside of the resin package, electrically connected to the semiconductor chip, wherein the resin package includes four side surfaces, an upper surface and a bottom surface, the four outer terminals are disposed respectively at four corners on the bottom surface, and each of the outer terminals extends along a selected one of the side surfaces and the bottom surface of the resin package.
According to an embodiment of the second aspect of the present invention, each of the outer terminals includes a drop portion extending along the selected side surface of the resin package, a bottom portion extending from the drop portion along the bottom portion of the resin package, and a riser portion extending from the bottom portion along another side surface of the resin package adjacent to the selected side surface.
According to another embodiment of the second aspect of the present invention, each of the outer terminals includes two branch portions, one of the two being bent to extend along the selected side surface and the bottom surface of the resin package. In this case, the other branch portion of each outer terminal extends along the selected side surface beyond another of the side surfaces adjacent to the selected side surface of the resin package. Alternatively, the other branch portion of each outer terminal is bent to extend along the selected side surface and another of the side surfaces adjacent to the selected side surface of the resin package.
Preferably, two of the four outer terminals are connected together by a first inner terminal, the remaining two of the outer terminals are connected together by a second inner terminal, the semiconductor chip is mounted on the first inner terminal, and the second inner terminal is connected to the semiconductor chip via a wire. Further it is especially advantageous that the connection between the second inner terminal and the wire is made generally at a longitudinal center of the resin package. Still further, if the semiconductor chip is a light emitting element or a light receiving element, the upper surface of the resin package may be provided with a convex lens portion at a location corresponding to the semiconductor chip.
According to a third aspect of the present invention, there is provided a semiconductor device comprising a semiconductor chip, a first lead connected to an electrode of the semiconductor chip, a second lead connected to another electrode of the semiconductor chip, and a resin package sealing the semiconductor chip, an inner terminal of the first lead, and an inner terminal of the second lead, wherein the semiconductor chip is mounted on the inner terminal of the first lead, the inner terminal of the second lead is connected to the semiconductor chip via a wire, the wire extends in parallel to one side surface of the resin package, each of the first and the second leads having at least one outer terminal extending out of the resin package from corresponding inner terminal through the side surface, and the connection between the inner terminal of the second lead and the wire is made generally at a center, as seen in plan view, of the resin package.
According to a preferred embodiment of the third aspect of the present invention, the semiconductor chip is a light emitting element or a light receiving element, and the upper surface of the resin package is provided with a convex lens portion at a location corresponding to the semiconductor chip. Further, the inner terminal of the first lead is provided with a tongue extending toward the second lead for mounting the semiconductor chip, and the inner terminal of the second lead is provided with a tongue extending toward the first lead for connection to the wire.
Other objects, characteristics, and advantages of the present invention will become clearer from the following description of embodiments to be presented with reference to the accompanying drawings.